snake_case writes a compound name in all lowercase with underscores between words, like user_profile_id. It is the standard convention for variable and function names in Python and for column names in SQL databases.

How does it convert camelCase input?

The converter detects the lowercase-to-uppercase transitions inside camelCase and PascalCase strings, splits at those points, lowercases everything, and inserts underscores. So userProfileId becomes user_profile_id.

Does it keep numbers?

Yes. Digits are preserved and separated from letters as their own segment, so http2Server becomes http_2_server. Rejoin a segment manually after copying if you prefer the digit attached.

What is the difference between snake_case and kebab-case?

They differ only in the separator: snake_case joins words with underscores (user_id) while kebab-case uses hyphens (user-id). snake_case is used in code identifiers; kebab-case is used in URLs and CSS.

Is my text uploaded anywhere?

No. The conversion runs entirely in your browser. Nothing you type is sent to a server or stored.

snake_case Converter

snake_case is the conventional naming style for Python identifiers and SQL columns: all lowercase, with underscores between words. This converter rewrites any phrase or differently-cased identifier into clean snake_case.

How it works

The input is normalised into a list of lowercase word tokens, then joined with underscores. Word boundaries come from separators and from case transitions in camelCase or PascalCase input:

"User Profile Id" -> user_profile_id
"userProfileId"   -> user_profile_id
"user-profile-id" -> user_profile_id
"HTTPServer"      -> http_server

Each detected word is lowercased before joining, so the result is always a valid, lowercase, underscore-separated identifier.

Tips and notes

Acronyms are lowercased, so parseHTML becomes parse_html. Letters and digits are split during tokenisation; if you want v2 to stay together, rejoin it after copying. The output is safe to use directly as a Python variable name or SQL column, provided it does not begin with a digit.